Visual signal detection as a measure for sustained attention and short-term remembering in mice exposed to methylmercury during adolescence

Abstract

Developmental methylmercury (MeHg) exposure is known to alter dopamine-mediated behavior associated with the prefrontal cortex. Exposure may be associated with symptoms of ADHD, such as inattention and impaired memory, which are also mediated by dopamine pathways in the prefrontal cortex. In order to assess this interaction, mice were exposed to 0, 0.3, or 3 ppm MeHg during adolescence and tested in a hybrid attention/memory task in adulthood in which mice detected a brief, unpredictable visual stimulus. Behavior was challenged by shortening the duration of a visual stimulus and introducing a novel distractor. MeHg did not alter behavior in this task. Attention was impaired at short stimulus durations and disrupted by the novel distractor, but this was not related to MeHg exposure. The lack of MeHg-related alteration in behavior in this procedure could be attributed to either differences in MeHg sensitivity during adolescence or to variations in the procedures used to assess attention/memory across species.